diff --git a/wx/lib/agw/aui/framemanager.py b/wx/lib/agw/aui/framemanager.py
index a3f2e431..44910ba5 100644
--- a/wx/lib/agw/aui/framemanager.py
+++ b/wx/lib/agw/aui/framemanager.py
@@ -2153,7 +2153,8 @@ class AuiSingleDockingGuide(AuiDockingGuide):
 
         useAero = (useWhidbey and [2] or [1])[0]
         bmp, dummy = GetDockingImage(self._direction, useAero, False)
-        region = wx.Region(bmp)
+        region = wx.Region(bmp, wx.Colour(0, 0, 0, 0))
+
         self.region = region
 
     def AeroMove(self, pos):
@@ -2340,7 +2341,7 @@ class AuiCenterDockingGuide(AuiDockingGuide):
         elif useAero:
 
             self._aeroBmp = aero_dock_pane.GetBitmap()
-            region = wx.Region(self._aeroBmp)
+            region = wx.Region(self._aeroBmp, wx.Colour(0, 0, 0, 0))
 
             self._allAeroBmps = [aero_dock_pane_left.GetBitmap(), aero_dock_pane_top.GetBitmap(),
                                  aero_dock_pane_right.GetBitmap(), aero_dock_pane_bottom.GetBitmap(),
@@ -2352,7 +2353,7 @@ class AuiCenterDockingGuide(AuiDockingGuide):
         elif useWhidbey:
 
             self._aeroBmp = whidbey_dock_pane.GetBitmap()
-            region = wx.Region(self._aeroBmp)
+            region = wx.Region(self._aeroBmp, wx.Colour(0, 0, 0, 0))
 
             self._allAeroBmps = [whidbey_dock_pane_left.GetBitmap(), whidbey_dock_pane_top.GetBitmap(),
                                  whidbey_dock_pane_right.GetBitmap(), whidbey_dock_pane_bottom.GetBitmap(),